Hi Rosso,
Looks like you have asked the same question twice hoping for the best. The reasons nobody replies could be numerous. Probably because you are new here - 2 posts. I think you will probably need to give a bit more before you take. There are heaps on here that can help. Is your RM flogged to death or hardly used? If the foot pegs are rattling and bent the motor/carb could have 200 hours+ of abuse, dust, the slide and needle are rooted, full of varnish and gunk. We can go on all day. What have you done/tried? What makes you say it's lean? Feels lean or IS lean? The plug is new and shows lean? Did you buy it in this condition or it was great last week and now seems lean... If you are new to this and everything above is not crystal clear I'd recommend (no offense here mind you) you do some reading and come back with answers to the questions nobody has asked, if you know what I mean, so we all know you have made some effort. I have a book on motorcycle tuning that SGall wrote for Yamaha from decades ago. There is also a great PDF on motorcycle carb tuning that covers everything. I mean, you may need to pull it down and simply clean it with carb cleaner, toothbrush and compressed air (or numerous other no abusive/corrosive methods) and be on your way to victory. Let's hear where your at?